The present disclosure relates generally to turbomachinery, and, more specifically, to methods and systems for providing a cooling system for component internal structures and component surfaces within gas turbines.
In at least some known gas turbines, in a component such as an airfoil or nozzle that is exposed to hot combustion gases, an internal structure within the component is cooled using cooling air or other fluid that is channeled through microchannels defined within the internal structure. Typically, the microchannels extend below and substantially parallel to at least a portion of an outer surface of the component. Cooling air is supplied to the microchannels from a cooling air supply passage that is also defined within the component and coupled to a source of cooling air. In at least some known gas turbines, the microchannels terminate in a trench that is oriented substantially perpendicularly to the microchannels. Typically, the trench defines an elongated opening in the component outer surface. After receiving heat from the internal structure of the component, the cooling air is exhausted from the microchannels and discharged into the trench and out through the elongated opening. The discharged cooling air defines a cooling air film adjacent to the outer surface that facilitates reduction of heat transfer from the hot combustion gases through the outer surface of the component into the internal structure.
It is desirable to improve an efficiency of the microchannels to facilitate more effective transfer of heat from the internal structure of the component into the cooling air, such that a lower cooling air flow rate is required, towards facilitating an improvement of an overall efficiency of the gas turbine.